To protect against data loss, a storage system can include a redundant array of inexpensive disks (“RAID”). The RAID level used for a RAID array depends on a number of factors including redundancy level, performance and reliability of the desired array. Standard RAID levels include RAID 1, RAID 4, RAID 5, RAID 6, etc. For example, in a RAID 5 array, data is striped across the plurality of disks in the RAID array. Additionally, the parity chunks in a RAID 5 array are distributed or staggered across the plurality of disks. In the event of disk failure, the chunk contained on the failed disk can be computed based on the chunks contained on the remaining (or neighboring, peer, etc.) disks of the RAID array.
In some cases, a RAID layer controlling the RAID array can be configured to fail a disk of the RAID array. For example, the RAID layer can remove a disk from operation in response to detecting a disk error. A RAID array operating with a failed disk is operating in a degraded mode. After analyzing the failed disk and, if necessary, repairing the disk error, the failed disk can be re-commissioned into the RAID array. In other words, the failed disk can be returned to operation. It should be understood that write input/output (“I/O”) operations can be received and executed while the RAID array is in the degraded mode. Therefore, when the failed disk is re-commissioned, the RAID array should be re-synchronized by restoring consistency to the data stripes of the RAID array. In related art, the entire failed disk is re-built in order to restore consistency to the RAID array. It should be understood that this process is both time-consuming and places increased load on the storage system.